I have a '04 CTT and recently had the GIAC flash done. I also have the flashloader to allow me to switch between "pump" mode (which is the tuned program for 93 octane) and "stock" mode. Everything else on the vehicle is stock. From reading everyone's testimonials about the GIAC flash, it should have been a pretty noticeable difference. However, from my observation, my "pump" mode feels the same as "stock". The boost gauge both in "pump" and in "stock" top out at .7 bar and level out to about .6 bar.

I also did a couple drag pulls against a friend of mine who has the same exact car, but completely stock. Every pull was dead even (PSM off, sport mode, low suspension). I also repeated this with putting my car back into "stock" mode, and again we were always dead even.

It's obvious that the "pump" flash had no effect and is identical to stock.

I contacted GIAC and they said the boost guage should definitely be pinned all the way to the right, at .8 bar or past it since their tune puts it at just over 1 bar and I should feel a very noticeable difference over stock. At their request, I took it back to the approved installer to have it reflashed, but the end result is the same even after another flash.

Has anyone with a GIAC tune ever experienced this before?

Thanks in advance for any help!

 

Have you checked your diverter valves?

 

I haven't checked the diverter valves. Do you think they're leaking any extra boost that I'm supposed to be getting?

 

x2....it's possible they're torn and leaking. If they're faulty..get a good set of Forge valves and you'll be all set

Forge Diverter Valves

(they're the same for a 996TT, Cayenne TT, or 997.2 TT)

 

Is a spike at .7 bar (later leveling to .6 bar) normal for stock boost? Would I notice diverter valve problems at the stock tune as well?

 

Not necessarily as the additional boost might be higher than the worn out DVs can hold. Maybe they can only hold .7 and releasing anything above it. But I would still be talking to GIAC. Upgraded DVs are a good idea regardless

 

From what I read, if you chose a tune and do not upgrade your diverter valves than you asking for trouble (read: torn stock diverter valves).

Considering the price of a good tune vs diverter valves (~$300), just factor it in as part of the upgrade price.

 

agreed. I know more about flashing audis than porsches and this is standard for audis.

 

We changed to Evo diverter valves. I agree that the valves helped a little. Feels like boost holds a little longer at .7 bar and seems to build quicker. However, the problem remains. The "pump" mode and "stock" mode remain identical.

 

The GIAC is a good tune- you should feel a night and day difference. I know I do whenever I switch between my stock tune and aftermarket tune.

The tunes are pretty straight forward and should work immediately- provided that you don't have a vacuum leak. If you already upgraded the DVs and are holding boost, then you should take a step back and look for something simple.

I would suggest calling GIAC and see if there could have been a mix-up there with your tune. I would also make sure that you understand how your aftermarket GIAC setup is supposed to work.

 

Give me a call and we can run through some potential options that will get your CTT up and running properly. As noted by many in this thread, the car should feel like a different animal if all is healthy.

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